Electric circuit-closing device



(No Model.) I

' W. C. JOHNSTON, Jr.

ELECTRIC CIRCUIT CLCSING'DBVICE.

No; 412,75 Patented Oct. 15. 1889.

WIT EssEs r.

W V UM. 7% VM d EJ UNITED STATES PATENT OFFICE.

WILLIAM G. JOH STON, JR, or LYNN, MASSACHUSETTS.

ELECTRIC CIRCUIT-CLOSING DEVICE.

- $PEOIFICA'IION forming part of Letters lPatent No. 412,758, dated October 15, 1889.

Application filed March 31, 1888.

Serial No. 269,123. (No model.)

is a specification.

Be it known that I, WILLIAM G. JOHNSTON, Jr., of Lynn, in the county of Essex and Commonwealth of Massachusetts, have invented certain Improvements in Electric Circuit-Glosing Devices, of which the following, taken in connection with the accompanying drawings,

This invention relates to an improvemen in devices for 'closin g electric circuits, and has for its object to provide ,means for preventing'dust from getting on and interfering with the contactterminals.

The nature of this invention is hereinafter fully described and then specifically claimed.

Referring to the drawings, Figure 1 is an elevation of a circuiteclosing mechanism embodying this invention. Fig. 2 is a similar view of a mechanism embodying a modified form of this invention.

The electrical conductors 2 2, the pushbutton 3, and contactterminals 4 4, and the connecting and supporting means therefor, are constructed in the usual and customary way. Connected with the same is a hood or covering a, which incloses the push-button and prevents all dust from entering under the same to work into the terminal points. The hood is for this purpose closely sealed or otherwise secured to the case A. This hood or covering is preferably made of rubber or a similar flexible material, to the end that it will permit being pushed inward for the purpose of allowing the push-button to be forced downward, thereby causing the contact-terminals' to bear upon each other for closing the circuit, and again return to its normal position when the pressing force is withdrawn.

In Fig. 2 of the accompanying drawings I have represented a modified form of this invention. It diders from the one shown in Fig. 1, in that the covering or hood consists of a sleeve portion e andan elastic diaphragm f. Ineither case the mechanism is operated for closing the circuit by pressing on the casing, in front of the push-button, at which point the flexible quality of the casing or cover allows it to be displaced by the inward pressure and carried forward to and along with the push-button, thereby obviating the necessity of getting to the push-button directly.

This invention is designed specifically for use in electric circuits now being used on railway-trains, in which the circuit-closing device is placed at the end of the car, and thereby subjected to the dust and cinders incident to a moving train.

Having thus described my invention, I claim- In combination, the electric circuit, a suitable casing, contact-points 4 Within the same, one of said points being movable, and a covering rigidly secured to said casing by its edges, whereby dust is excluded therefrom, the said covering being composed of flexible material and arranged independent of the movable contact point but in proximity thereto, in order to move the same when pressed upon, substantially as described.

Signed at Boston this 18th day of March,

WILLIAM C. JOHNSTON, JR.

Witnesses:

O. B. TUTTLE, E. E. HAMILL. 

